Delayed Pressure Urticaria: Clinical and Diagnostic Features and Response to Omalizumab.

Background: Delayed pressure urticaria (DPU) is a rare form of chronic inducible urticaria (CIndU) when it manifests alone. Treatment of DPU is disappointing owing to the lack of response to antihistamines, even when up-dosing. In addition, the absence of randomized clinical trials and the low number of patients included in the studies mean that there is little scientific evidence for the validity of omalizumab in DPU.

Objective: Objectives of the study were to perform a real-world study of the effectiveness and safety of omalizumab in DPU patients without chronic spontaneous urticaria or other forms of CIndU and to describe their clinical and diagnostic features.

Method: We performed an ambispective observational study of 14 patients with DPU who did not respond to 2 or more second-generation H1-antihistamines in an up-dosing regimen and/or corticosteroids, montelukast, or cyclosporine. Treatment was initiated with omalizumab 300 mg every 4 weeks. We recorded the following: age, time to diagnosis, previous treatment, diagnostic testing (mean time threshold after removing the stimulus and duration of the lesions), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), D dimer, total IgE, antithyroid peroxidase (anti-TPO) antibodies, and the Urticaria Control Test (UCT) score before and after the first dose. We evaluated the efficacy of omalizumab according to the Urticaria Control Test score. We analyzed the time to complete or satisfactory response after the first dose (superfast) and its adverse effects.

Results: Women accounted for 64.28% patients. The mean age at diagnosis was 43.64 (±13.78) years. The time to diagnosis was 4.53 (±5.54) years. The mean time threshold after removing the stimulus was 4.18 h (±2.75). The mean duration of lesions after testing was 32.42 (±13.8) hours. High ERS values (>20.0 mm/h) were detected in 50% of patients. CRP was >0.5 mg/dL in 42.85% and D dimer levels were high (>500.0 ng/mL) in 3/10 patients. Anti-TPO level was normal in 100% of patients. Total IgE was >100 IU/mL in 6/8 patients. Medium UCT levels before treatment with omalizumab were 3.07 (±2.40), reaching 15.28/16 (±1.72) after the first dose of omalizumab. All 14 patients responded superfast, and none experienced an adverse reaction.

Conclusions: Despite the limitation of a low sample size in this real-life study, our findings suggest that omalizumab is a rapid, effective, and safe treatment for patients with DPU refractory to antihistamines in an up-dosing regimen. We recommend omalizumab for patients who do not respond to up-dosing antihistamines and montelukast.